Generally, casement window sashes are mounted to the window frame by hinges. These hinges may be attached either to the bottom of the window sash, or to the top of the window sash. Conversely, the hinges may be attached to both. It is typical for such a hinge to have a track mountable to the window frame. The sash arm is generally pivotally connected to a mounting shoe block, which is supported and guided, for movement lengthwise across the track. Window hinges of this type are shown, for example, in Tacheny et al. U.S. Pat. No. 4,726,093, and Sandberg et al. U.S. Pat. No. RE32,846. In normal operation when the user wishes to open a casement window, let's say, for ventilation purposes or cleaning, the user will turn a crank handle in a clockwise motion, for opening the casement window, and in a counterclockwise motion, for closing the casement window. After repeated opening and closing of a casement window, the window may eventually move out of a squared position, which in turn may prevent the window sash from fully closing, thus preventing the keeper, in the casement window frame, from engaging the latch; this can be burdensome to the user. So then, why do crank-out windows become hard to close after a few years? The answer is what is known in the window industry as “sash sag”. Sash sag has been stated as “the single most asked question concerning the operating casement window today”, but as research has shown there is no simple, clear cut solution to the problem. For purposes of definition, we define the problem of sash sag as the movement of the sash relative to the window frame. The first step toward gaining an understanding of sash sag is to identify the causes. One possible cause of sash sag is something that is referred to as “sash drag”, whereby the sash will drag across the frame or sill as the window is opening or closing. Usually this problem is due to the bottom corner of the latch side of the sash dragging against the frame.
There are many reasons why the sash of a casement window may begin to drag against the window frame: the sash may sag out-of-square because of improper hinge positioning, improper glazing, and poor track attachment by the manufacture, or the frame may settle out of square because of poor installation.
Glazing compounds used by the manufacturers have been observed to take a considerable period of time to set up. During this time it is possible and likely for the sash to sag around the glass thereby possibly moving the sash out of square. Another cause of sash sag attributed to the manufacture is hinge positioning. This is the relationship of the top hinge to the bottom hinge and the side jamb; hinge positioning is critical in window manufacturing. Because of certain manufacturing tolerances in each hinge, there can be as much as 0.019″ lateral movement of the arm assembly within the track, which will accelerate the effects of sash sag in most residential casement windows. Yet another manufacturing defect that will further accelerate sash sag is the improper fastening of the track screws. If the track screws are not driven down as straight as possible, then the track will twist over time, and cause the sash to sag. In addition, there are some types of hinges that have track protrusions which are designed to sink into soft frame materials such as wood. However, sometimes these track protrusions do not fully sink in when the screws are tightened. This condition may allow the track to shift or rotate and contribute to the sash sag. There are some tracks that have a special flat bottom hinge track, as in the present invention, specifically designed for mounting on hard frame materials.
Improper installation of the casement window is the second leading cause of sash sag, regardless of whether a frame leaves the manufacturer without any defects, and is in a square configuration or not, it must be placed into the roughed out opening and secured as squarely as possible. Any deviation from a square frame can result in apparent sash sag. In addition, casement windows which are square (shape) or wider than they are tall compound sash sag problems due to added cantilevered weight. Some experts recommend that when designing and/or specifying a casement window, the sash width should be limited to 66% of the sash height. Once again, any length discrepancies in sash or frame parts will result in the sash or frame being out of square.
Sash sag is a potential problem that requires close control at all levels of the window industry. This control must be exhibited with those who manufacture component parts as well as those who assemble, transport and ultimately install window units. Each item listed above helps add to the compounding of the sash sag problem and it is possible for one or any combination of the above problems to exist!
The earlier methods of correcting the problem of sash sag usually required that the hinge track be provided with slotted holes and that the hinge mounting screws in the slotted holes were to be removed to allow for shifting of the track. Repeated removal of such screws can, however, over the life of a window result in gradual loosening and depleted integrity of the window. In more recent times, sash sag has been corrected with the use of an adjustable hinge. One such type of adjustable hinge that has been employed is that of U.S. Pat. No. 5,152,102 and U.S. Pat. No. 5,074,075, issued to LaSee. In that prior art the inventor implemented an octagonal cam mechanism, so as to allow for sash sag compensation. More recently, U.S. Pat. No. 5,307,539, issued to Bauman, utilized an eccentric shaped adjustable stud, having a flange with surfaces for engaging an adjustment tool, having a pivot portion, about which the swivel arm pivots, and an eccentric neck, frictionally secured to the window frame or the track, about which the pivot axis rotates when the alignment is adjusted. However, this prior art required the user to engage a wrench, the adjustment tool, roughly perpendicular to the hinge axis. Because of the tight spaces associated with casement window hardware, this type of adjustment method can be unduly burdensome to the user. This stud type adjustment was improved upon in U.S. Pat. No. 5,964,011, assigned to Newell, by having the tool access position, in which the tool is engageable with the engagement stud, roughly parallel to the pivot axis. However, this type of configuration is unnecessarily complex with a multitude of different members, which may amount to possible malfunctions of the different members, and an added cost to production. In the present invention, the hinge may be adjusted simply, with the twist of screwdriver, or the simple twist of a finger. This is because of the simplified adjustment post, which consists mainly of a threaded screw and a threaded aperture.